The problem of providing optical structures that obtain a high coupling efficacy between an optoelectronic device (such as an optical radiation emitter or receiver) and a waveguide (such as an optical fibre) has been felt for a long time. Particularly, there are applications such as optical communication requiring an LED (Light Emitting Diode) emitter or diode photo-detector PIN to be coupled with an optical fibre while minimizing the scattered optical power.
To this end, U.S. Patent Publ. No. 2004/0008952A describes a coupling device which includes an LED diode fixed on a substrate and a mechanical coupling body made of plastic with a cavity partially occupied by an optical fibre formed therein. The part of this cavity which is not occupied by the optical fibre has its walls covered with metal and having such a profile as to reflect the radiation emitted by the LED to the optical fibre. The portion of the cavity covered with metal is filled with a clear adhesive that bonds the fibre, thereby holding the same in position.
WO 2004/084317 describes a device having a photodiode mounted on a support structure about which an epoxy, clear body is moulded. It incorporates a lens intended to focus light originating from a fibre on the photodiode.
The coupling optical modules manufactured according to the prior art suffer from drawbacks and restrictions with respect to coupling efficacy (e.g., low tolerance to misalignment), complexity and manufacturing costs.